ci(codeowners): un-trap required checks, auto-render, generate owner tables (#142)

The CODEOWNERS required checks blocked every PR — the real root cause was a
name mismatch, compounded by a path filter:

- branch-protection.json required the contexts `CODEOWNERS / drift` and
  `CODEOWNERS / noedit` (the GitHub UI "workflow / job-id" display form), but
  the jobs report check-run names from their `name:` fields — "CODEOWNERS
  matches source" / "CODEOWNERS not hand-edited". The required contexts
  therefore never matched any reported check and sat permanently pending.
- The workflow was also path-filtered to CODEOWNERS files, so it didn't even
  run for most PRs.

Net effect: with both required checks unsatisfiable, every PR could only land
via admin override (e.g. #140).

Fixes:
- A: drop the `paths:` filter so the workflow runs on every PR and both
  required contexts always report.
- name fix: point branch-protection.json at the actual job names verbatim, and
  add a doc note that the contexts must equal the job `name:` values.
- B: the `drift` job now re-renders and, on same-repo PRs, auto-commits the
  regenerated artifacts back to the branch (mirrors the openapi.json job in
  ci.yml); forks / manual runs strict-check instead. Contributors no longer
  run the script by hand.
- D: render-codeowners.py also generates a "who owns what" path->owners +
  roles table spliced into docs/dev/codeowners.md between markers, so the
  human-readable view never drifts. Idempotent; CODEOWNERS output unchanged.
- docs: correct the stale `enforce_admins: true` line (JSON and live are
  false).

NOTE: the branch-protection.json change only takes effect after an admin runs
`./scripts/apply-branch-protection.sh` (deliberate manual step, per
docs/dev/branch-protection.md). Until then `main` still requires the old
mismatched contexts, so this PR itself needs an admin-override merge — the last
one that should be necessary.

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.github/branch-protection.json

@@ -7,8 +7,8 @@
       "Check AGENTS.md Links",
       "Test Workspace",
       "Test omnigraph-server --features aws",
-      "CODEOWNERS / drift",
-      "CODEOWNERS / noedit"
+      "CODEOWNERS matches source",
+      "CODEOWNERS not hand-edited"
     ]
   },
   "enforce_admins": false,